A Review of Megahertz Current Sensors for Megahertz Power Converters

Abstract

Within a power converter, multiple currents are usually measured for control, protection, and/or monitoring. They are therefore important sources of information, which must unquestionably be measured accurately to maintain continuous and reliable operation of the power converter. Accurate current measurement has however become tougher with the introduction of wide band-gap (WBG) devices with switching frequency tending towards the Megahertz (MHz) range. Because of that, the installed current sensors must have a significantly widened bandwidth. Moreover, they must be nonintrusive and compact, in order not to degrade fast switching characteristics and high power density of the WBG converter. Presently, these features are not collectively obtainable from existing commercial current sensors. Consequently, many new current sensing techniques have surfaced in the literature for usage with the more demanding MHz power converter. These new techniques, some classical techniques, and their hybrid integrations are now reviewed, after overviewing functionalities made possible by current sensors in a power converter. Last but importantly, some future developmental trends aimed at matching MHz current sensors with MHz power converters are described, before concluding the paper.

High-Frequency Current Transformers Cascade for Power Electronics Measurements

“…Precise current measurement in power electronic systems is necessary for the operation of the closed control system and for the implementation of calculation algorithms [ 1 , 2 ]. Resistance current sensors with high band up to 2 GHz [ 1 , 2 , 3 , 4 , 5 ] are called current shunt resistors (CSR).…”

“…Precise current measurement in power electronic systems is necessary for the operation of the closed control system and for the implementation of calculation algorithms [ 1 , 2 ]. Resistance current sensors with high band up to 2 GHz [ 1 , 2 , 3 , 4 , 5 ] are called current shunt resistors (CSR). The disadvantage of such resistors is the introduction of additional elements into the electronic circuit, which changes the topology of the system and introduces additional losses [ 1 , 2 ].…”

“…Resistance current sensors with high band up to 2 GHz [ 1 , 2 , 3 , 4 , 5 ] are called current shunt resistors (CSR). The disadvantage of such resistors is the introduction of additional elements into the electronic circuit, which changes the topology of the system and introduces additional losses [ 1 , 2 ]. The CSR can also be designed for high currents [ 5 ].…”

“…Hall sensors [ 1 ] are other current sensors that transfer both the DC and the variable component. The advantage of the sensor is the complete isolation of the measurement, and its disadvantage is a relatively low-frequency response.…”

“…The Rogowski coil allows for the measurement of high currents because it has no core (no saturation). The advantage is the small size of the measuring coil [ 1 ] and the possibility to design the coil in the form of a printed circuit [ 10 ]. Its disadvantages include the relatively low-frequency response for high frequencies [ 11 ].…”